Traveler’s diarrhea is very common. Travelers often expect the same standards as at home even in areas where sanitation is not common place. Infections often start in restaurants and bars, when there are no food inspections or hygienical standards. The most common cause is E.coli (non-problematic strains). Nausea, vomiting, abdominal pain and diarrhea occur ½ to 3 days after the traveler ingested food or water with contamination.
For prevention the traveler has to take bismuth subsalicylate suspension (at a relatively high dose of 60 ml four times daily) for it to be effective. When there is diarrhea with bloody stools, the infection experts recommend treatment with sulfamethoxazole/ trimethoprim (Bactrim, Sulfatrim, Septra) or ciprofloxacin (Ciloxan, Cipro) for adults. Children under 16 years are not allowed to take ciprofloxacin, but can take sulfamethoxazole/ trimethoprim.
Some of the common pathogens in Traveler’s diarrhea
Several antibiotics are effective against the campylobacter bacterium (Ciprofloxacin, brand names: Ciloxan, Cipro) is used for 5 days or alternatively azithromycin (Zithromax) for 3 days. Alternatively erythromycin (Ery-Tab, PCE, Eryc, Erythromid) would also be effective. Normally it affects the lining of the gut. In complicated infections with sites other than the gut infected, sometimes up to 4 weeks of antibiotic therapy has to be given in order to prevent recurrences.
The flagellated protozoan Giardia lamblia can colonize the intestinal tract and either cause flatulence, malabsorption or frank watery diarrhea. Treatment for it is metronidazole (Flagyl, Metric 21), but this cannot be given to pregnant women. A pregnant woman, however, could use the non absorbable aminoglycoside, paromomycin sulfate (Humatin).
In many patients with a normal immune system this form of gastroenteritis with cryptosporidium parvum is self limiting. However, in AIDS patients and in immunocompromised patients because of chemotherapy or because of immunosuppressive medication for organ transplants this form of gastroenteritis could become a major problem with frequent and large watery bowel movements. Paromomycin (Humatin) seems to be the most successful antibiotic for this. At least in some AIDS patients antiretroviral therapy seems to also control the symptoms of cryptosporidiosis.
Amebiasis (also amoebiasis or entamebiasis)
This protozoan form of gastroenteritis involving the parasite Entameba histolytica can be asymptomatic, can be moderately symptomatic with bloody diarrhea, but it can also be a severe illness. In this latter case the amebiasis can spread via the portal vein system into the liver, where it can produce liver abscesses. From there it can spread further through the blood stream into lungs, brain or other vital organs. The abscess can also rupture into the right abdominal cavity or the right chest cavity. By that time the patient is very sick. However, it is exceedingly difficult to diagnose this condition, which would involve CT scans, ultrasounds and special immunoassays.
Treatment of Entameba histolytica
Treatment consists of drugs like metronidazole (Flagyl, Metric 21), emetine or dehydroemetine in combination with chloroquine. The gastroenterologist likely will know of newer agents that he would use for this serious condition. When treatment is finished there should be follow-up stool examinations at 1, 3 and 6 months to ensure that treatment was effective.
Cyclosporiasis and Isosporiasis
These more rare protozoans that can be a cause for gastroenteritis have come more into the forefront because of AIDS patients who can have problems with ongoing gastroenteritis involving these parasites, whereas people with a normal immune system have no or very little symptoms. Sulfamethoxazole/ trimethoprim (Bactrim, Sulfatrim, Septra) is effective for both of theses parasites. There are alternatives, if a person is allergic to this antibiotic.
This protozoan called microsporidia can cause severe diarrhea in immunocompromised patients such as AIDS patients or cancer patients on chemotherapy. This protozoan can migrate from the bowel wall to the liver and produce hepatitis, also cause infection of the abdominal cavity (peritonitis) and infection of the bile ducts (cholangitis). Other frequently infected organs can be the muscles (myositis), kidneys, gallbladder, sinuses and the outer eye (keratoconjunctivitis). None of the treatments are curative, but albendazole has been reported to have a partial controlling effect and fumagillin eyedrops and fluconazole or itraconazole have been somewhat successful for the eye involvement.
About 25% of the world population is infected with the hookworm. There are different subtypes. The Necator americanus is the hookworm that is prevalent in the Southern United States, in Central and Southern Africa. The other widely distributed hook worm is called Ancylostoma duodenale. It is mainly found in the Mediterranean, Japan, China ,India and parts of South America. Colicky abdominal pain, flatulence and diarrhea are found in these patients. Weight loss, an iron deficiency anemia and an allergic white blood cell picture (eosinophilia) are other features. Treatment consists of mebendazole (Vermox) for three days with a cure rate of almost 100%. Pregnant women are not able to take this, but there is alternative medicine available for them. Ask your doctor.
Treatment of Traveler’s diarrhea
Treatment for Traveler’s diarrhea has to be individualized. See your doctor as stool samples may have to be sent. Depending on what the severity of the symptoms and what the underlying pathogen is the treatment may vary a lot. Fluid loss needs to be replaced. Prevention of further infestation needs to be watched for.
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